go and buy some decon rat poision. put it under your fridge and other low to the ground appliances and right in front of the holes. you wont see any more mice poop for a while. i know for a fact that this works because i am from iowa and grew up in the middle of a corn field and every year during the harvest it would drive all the thousands of mice out of the fields and looking for shelter. and our old farm house fit the bill. we tried a cat. traps, live traps. nothing worked then we got this decon stuf. and man it kills the H out of them. carefull you cats and dogs dont get in to it.
matt
p.s. and it decomposes them so they dont stink. also a pluss.